The Downloads page includes a curl command under "Install Script". It should link to https://dlang.org/install.html. I recommend adding before the curl command: "The install.sh script is the official D version manager for DMD, GDC and LDC on FreeBSD, Linux and macOS. It provides a convenient way to fetch and install a D compiler without requiring administrative privileges or external dependencies. For more information, see [link to https://dlang.org/install.html]."
This issue is now being dealt with in this PR: https://github.com/dlang/dlang.org/pull/2154